You should be clear about that when you suggest jumping into a repair that if done wrong or poorly will cost the reader more than if they just brought it to a pro in the first place.
If you bolt a valve cover down wrong, a leak is pretty much a worst case...If they Don't have the tools to get ring gear bolts torqued correctly they can wind up in the ditch or worse. Not to mention repairs of now broken housings and mangled gears and diffs. A sye is simple if you have been into one before or have knowledge of something not feeling right on a preload or torque enough to go back in and diagnose what went wrong.

If you can't afford to do it twice or more, the learning curve gets pretty steep.

SD